Neutron-induced fission cross sections for natPb and 209Bi were measured with a white-spectrum neutron
source at theCERNNeutron Time-of-Flight (n TOF) facility. The experiment, using neutrons from threshold up to
1 GeV, provides the first results for these nuclei above 200 MeV. The cross sections weremeasured relative to 235U
and 238U in a dedicated fission chamber with parallel plate avalanche counter detectors. Results are compared with
previous experimental data. Upgraded parametrizations of the cross sections are presented, from threshold energy
up to 1 GeV. The proposed new sets of fitting parameters improve former results along the whole energy range.